Cooling System Pressure Cap Testing
| 1 - PRESSURE CAP |
| 2 - PRESSURE TESTER |
Dip the pressure cap (1) in water. Clean any deposits off of the vent valve or seat and attach the cap to the end of the Pressure Cap Test Adapter that is included with the Cooling System Tester (special tool #7700, Tester, Cooling System). Working the plunger (2), bring the pressure to 104 kPa (15 psi) on the gauge. If the pressure cap fails to hold pressure of at least 97 kPa (14 psi), replace the pressure cap.
The Cooling System Tester Tool is very sensitive to small air leaks that will not cause cooling system problems. A pressure cap that does not have a history of coolant loss should not be replaced just because it leaks slowly when tested with this tool. Add water to the tool. Turn tool upside down and recheck pressure cap to confirm that cap is bad.
If the pressure cap tests properly while positioned on Cooling System Tester, but will not hold pressure or vacuum when positioned on the filler neck, inspect the filler neck and cap top gasket for irregularities that may prevent the cap from sealing properly.